Chicago police Superintendent Garry McCarthy, joined by law enforcement brass and prosecutors from across the country, called Wednesday for major changes how the criminal justice system handles low-level offenders, a message he and others plan to take to the White House.

The group McCarthy co-chairs, Law Enforcement Leaders to Reduce Crime & Incarceration, unveiled four policy priorities they said would halt mass arrests and reserve costly prison beds for violent, career criminals.

The group wants to increase alternatives to arrest and prosecution, especially for people with mental health problems and drug addictions who could be diverted into treatment.

It proposes downgrading some felony offenses into misdemeanors and, in some cases, removing criminal sanctions altogether. It hopes to curb or end mandatory-minimum sentences that lead to what the group called "overly harsh, arbitrary" prison stays. And it wants to strengthen ties between law enforcement and the community.

Asserting there is a crisis in today's policing, McCarthy said it may be radical idea, but thought must be given to what constitutes a crime. He said his own thinking had "morphed" over the years.

"If you put a gun in somebody's face and say, 'Give me your money,' that's a crime. And if you get caught with 10 bags of heroin, do you think that those two crimes should carry the same weight in the criminal justice system? It just doesn't make sense," McCarthy said.

He and others spoke at an event at the National Press Club.

Los Angeles Police Chief Charlie Beck noted that he had been through the war on drugs and the war on gangs and said departments shouldn't be "at war with the communities that they serve."

President Barack Obama will address the International Association of Chiefs of Police annual conference in Chicago on Oct. 27, a White House official said Tuesday.

The law enforcement gathering opens Saturday at McCormick Place West and runs through Oct. 27.

The meeting is the world's largest gathering...

President Barack Obama will address the International Association of Chiefs of Police annual conference in Chicago on Oct. 27, a White House official said Tuesday.

The law enforcement gathering opens Saturday at McCormick Place West and runs through Oct. 27.

The meeting is the world's largest gathering...

(Katherine Skiba)

"We've come to recognize that the issues that we deal with cannot be solved by merely locking people up and throwing away the key," said Beck, who touted treatment programs and, for people leaving jail cells, re-entry programs.

McCarthy said the notion of Chicago having the toughest gun laws in the country was "rhetoric that somebody created that gets repeated over and over."

After the event, McCarthy told reporters he favored stronger penalties for straw buyers and for illegal gun possession. He wants mandatory reports required when a firearm is lost, stolen or transferred, saying that mandate would curb straw purchases.

He also backs universal background checks and bans on assault weapons and high-capacity magazines. "We recover assault weapons with 100-round magazines," he told reporters. "Just think about the firepower and the devastation that that gun can cause."

McCarthy and other officials plan to be at the White House Thursday when, according to a news release, President Barack Obama will join a panel discussion on how to make law enforcement and correctional practices "more just and effective."

Obama visits Chicago on Tuesday to address the annual conference of the International Association of Chiefs of Police.

Planned appearances at Wednesday's event by New York City Police Commissioner William Bratton and New York District Attorney Cyrus Vance were canceled after a plainclothes police officer in New York City was shot and killed Tuesday night. His death was acknowledged in a moment of silence for "condolence and reflection."